This invention relates to a method and apparatus for processing photographic material, and more particularly to a developing basket assembly and tank for processing exposed sheets of photographic material and the method of processing.
From the beginning developments in photography, the actual picture taking has been only an initial step in the involved process leading to the final product, a photographic print. Over the years, many inventions designed to make photographic development better in quality and more efficient have been introduced. Nevertheless, the developing processes remain complex and involved. The advent of color photography has added even more complexity to the developing processes.
The most basic photograph processing is accomplished by the single sheet tray-to-tray method for development. This involves individually dipping a single sheet of exoised photographic material into various trays containing the different developing solutions in accordance with time intervals in the processing sequence. Naturally, this process consumes much of an operator's time and effort and at the end of the long process he produces only one processed print.
Subsequent developments improving the equipment and methods for photographic print processing include the color canoe, drum processors, and basket and tank assemblies. With the color canoe, the operator places a single exposed photographic sheet in the canoe-like structure that floats on water and then pours in the developing fluids. By depressing and releasing one side of the floating canoe, it rocks back and forth in the water thereby sloshing the developing solution over the photographic sheet. The color canoe frees the operator from the constant dipping action which is required by the tray-to-tray method, but is still limited to processing one print at a time. The drum processor further simplifies the photographic print developing processes by introducing an apparatus that permits some of the processing steps to be performed in a lighted room. With a drum processor, the operator inserts an exposed photographic sheet into a cylinder and caps the end while in a dark room. Then with the lights on, the operator pours in the developing fluids through a light-trap opening. The cylinder is then rolled back and forth to slosh the fluid over the sheet. Again, the major disadvantage is that only a single sheet or at most two or three sheets can be developed at one time.
In order to develop a plurality of exposed sheets at once, operators use a complex assembly of devices including print holders and various tanks. One form of holder uses individual frames for each photographic sheet. Each individual exposed sheet is loaded into a separate frame and the loaded frames are then inserted into the holder. The frames of this type of holder tend to inhibit the flow of the processing fluids and complicate the steps necessary for loading the exposed sheets into the holder in a dark room. Other types of holders use only side panels with grooves or other means to hold the edges of the photographic sheets. These holders allow very little of the desirable turbulence which is needed for uniform development. Furthermore, these holders provide no positive separation at the middle section of the photographic sheets. Thus, the prints are often unevenly developed or have imperfections which are caused by the exposed sheets touching each other during the developing process. Still other holders use screened compartments or side panels to separate individual exposed sheets. These types of screened compartments frequently cause shadows of the screen to appear on the developed sheet. All of these types of holders which use one form or another of separating structure for the exposed photographic sheets are difficult to load in the dark.
In addition to the above disadvantages, the holders frequently have perforated sides or bottoms. These perforations allow the developing fluid to contact the exposed photographic sheets. However, the perforations or openings do not direct fluid flow or control the amount of turbulence which is created during processing, thus, the sheets frequently have swirling shadows or uneven development which is caused by over turbulence or erratic fluid flow during processing.
Many forms of processing tanks are used in conjunction with these various holders. Most processing tanks are rectangular structures and are constructed of metal materials, such as stainless steel. These tanks are heavy, but nevertheless, tip over easily when inadvertently jarred. The use of other materials, particularly plastics, for processing tanks has been shunned because these materials tend to bow and weaken from the pressure that the developing fluids exert on the tank walls. Many processing tanks include complex and expensive accessories for maintaining certain temperatures or desired turbulence in the developing solutions. To create the desired turbulence one processing tank uses an expensive and complex means for introducing gas bubbles into the processing tank so that the exposed sheets in the basket are evenly developed. The tanks presently being used are expensive to construct and manufacture.
Some of the above described holders and tanks are now available in the marketplace, the cost of a complete processing system capable of simultaneously processing a plurality of substantially unspoiled prints is prohibitive for the amateur photographer market. Nonetheless, the continuous refinement of print processing holders and tanks demonstrate the desirability of having certain as yet unobtained features in a print processing system. The print holder and tank assembly must be easy to operate in a dark room because an exposed sheet must not be subjected to light during processing. A holder must securely retain and separate the sensitive exposed surfaces of a plurality of sheets to permit the processing solution to engulf and slosh over the sheets during developing to prevent imperfections caused by the sensitive sheet surfaces touching each other. The holder must permit a certain degree of turbulence in the developing fluids and direct the fluids between the plurality of exposed sheets to provide for uniform development of each sheet. Additionally, the processing tank must be durable and sturdy, resistant to tipping over, easy to manufacture, and light-weight.
An object of the present invention is to provide a processing basket with a fluid directional control that creates the desired fluid turbulence when it is mildly agitated within a tank containing the processing fluid.
Another object of the present invention is to provide a processing basket that firmly secures and segregates the sensitive exposed sheet surfaces on all sides by using minimal contact at the sheet edges.
A further object of the present invention is to provide a processing basket which may be easily loaded with a plurality of exposed photographic sheets in a dark room.
Still another object of the present invention is to provide a processing tank for receiving the basket and which is stable and resistant to being tipped over.
A still further object of the present invention is to provide an affordable light-weight basket assembly and processing tank system which is relatively inexpensive to construct, yet sturdy and durable.
Finally, another object of the present invention is to provide a method for processing a plurality of exposed photographic sheets by using a basket assembly and developing tank system.
Other objects and advantages of the invention will become apparent upon reading the following detailed description and appending claims, and upon reference to the accompanying drawings.